(a) Field of the Invention
This invention generally relates to a device and method for fusing joining cervical vertebra. More particularly, but not by way of limitation, to a cervical plate having graduated thickness and a method for using the same.
(b) Background
The fusion of sections of the spine using plates that are mechanically fastened to the vertebra is a well-known method of treating problems associated with diseased or injured areas of the spine. The cervical region of the spine presents distinct anatomical limitations to the design and application of these plates. Cervical plate fusions are typically accomplished through the anterior of the cervix. Anterior cervical plates need to be thin (2-2.5 mm) to avoid esophageal injury, especially at mid to upper c-spine. Most degenerative disease occurs at C5-6, C6-7 Lower c-spine and C-thoracic anterior fixation is difficult because of anatomy (sternum). The ability to compress an inter-body graft at time of surgery is desirable, and believed to lead to increased fusion rate. Increased screw length leads to increased pullout strength with convergent (divergent) screws.
Vertebral body size increases from cephalad to caudad, while Sagittal roll increases from cephalad to caudad. Prevertebral space increases from cephalad to caudad.